Political uncertainty over Greece’s proposed exit from its international bailout programme hammered the Athens stock market on Tuesday.

The main index slumped 5.7 percent.

At the same time the cost of borrowing for the Greek government rose; the amount of interest that had to be offered on bonds maturing in 10 years was up above 7.0 percent for the first time since March.

Also playing into investors fears was the risk of a snap election early next year, which the main opposition party would likely win; it advocates a significant writedown of Greece’s debt.

Discussions have been going on between Greece and its eurozone partners about on a new line of credit with the European Stability Mechanism, a source told Reuters earlier in the week.

Germany’s Handelsblatt newspaper earlier quoted German government sources saying a precautionary credit could help ensure Athens stuck to a programme of economic reforms prescribed by the EU in return for a bailout of public debt.

The Athens government is in negotiation with EU institutions and the International Monetary Fund ahead of the expiry of its bailout package with the European Union on Dec. 31. Greece has said it wants its bailout to finish when EU funding stops, though the IMF is scheduled to stay through to early 2016.

An exit from supervision by the widely resented international “troika” of lenders — the European Commission, European Central Bank and International Monetary Fund — would be popular with voters.